Flight Reliability
DL 847 · Delta Air Lines
Salt Lake City → Washington (SLC–IAD)
85
Pretty Reliable
WanderNerd Reliability Score
- 84%
- Arrive within 15 minutes
- 2 min
- Average arrival delay
- 1.6%
- Cancelled
- 8 min early
- Median arrival delay
Based on 364 historical flights. Data through May 2026.
What the data says
The late departure is the smart one here.
DL 847 departing between 6–9 PM arrived on time 96% of the time, versus 83% between 3–6 PM.
Sunday scaries are real for this one.
DL 847 arrived on time 90% of the time on Tuesdays and just 75% on Sundays. That gap is worth planning around.
Slipping a little lately.
DL 847 arrived on time 84% of the time over the last three months in the data, compared with 89% in the three months before that.
The breakdown
- Mon88%(50 flights)
- Tue90%(51 flights)
- Wed82%(51 flights)
- Thu86%(51 flights)
- Fri79%(52 flights)
- Sat87%(52 flights)
- Sun75%(51 flights)
- 3–6 PM83%(336 flights)
- 6–9 PM96%(22 flights)
81%
May
Jun 60% → May 81% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 60% | 30 |
| July 2025 | 68% | 31 |
| August 2025 | 97% | 31 |
| September 2025 | 87% | 30 |
| October 2025 | 81% | 31 |
| November 2025 | 97% | 29 |
| December 2025 | 93% | 30 |
| January 2026 | 83% | 29 |
| February 2026 | 92% | 26 |
| March 2026 | 80% | 30 |
| April 2026 | 90% | 30 |
| May 2026 | 81% | 31 |
- Departures on time
- 84%
- Diverted
- 0%
- Flights flown
- 358
- Months covered
- 12
Same route, other flights
Keep nerding
Based on 364 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.